The de Blasio administration is proposing a 30-cent surcharge on all yellow and green cabs as part of an effort to make half of New York’s fleet wheelchair-accessible by 2020, Capital New York first reported on Tuesday. The money would be used to convert the cars into wheelchair-accessible vehicles, as well as to cover “wheelchair passenger assistance training” for drivers. A Taxi and Limousine Commission hearing on the change, which would begin in 2015, is scheduled for April.